Anyone doing an oldies format and play major hits may be unknowingly playing re-recordings and not the original hit recording. The remake claim of original artists are also a lie as the original group members and singers and musicians are not even on the new version. And a singer that was 17 or 18 at the time, and younger, can't sound the same at 40 or 50.
The dilemma of remakes started when, in the eighties, when CDs were a new thing older eras were not available on CDs so companies started making compilations CDs of 40s 50s 60s 70s hits and mostly the major hits and didn't take the songs from the originals but had artists redo them. Not all did this but the majority. Not only did the songs not go and sound anything like the original, not sung the same, and not sound like the times they were recorded in but the disclaimers on most of these CDs state that selections are re-recorded by the original artists but may be by a different singer, group members, etc. but they claim "original" artists.
In all these CD compilations if it doesn't say original hits or original recordings they are not the genuine recording that you are familiar with from the radio or the record back when it was a hit. Some are so bad! if you listen to "At The Hop" by Danny And The Juniors and you know the original and then hear the re-record it makes you sick! This example applies to countless remakes...100s, 1000s. Two companies that put out compilations CD sets...Rhino and Time Life have stayed true to the originals. There are others too that also include lesser hits and more obscure songs that are all originals but you have to do your research to find them if CDs are where you are getting your playlist from. Also CDs that feature a certain record company like Cadence for example are originals. If you get CDs on Amazon you have to look for a picture that it states original recordings/hits and many you can sample but you have to know yourself.
Youtube is good 90% of the time but you have to know the original to know a remake. Usually there is several videos of a certain song and one may be a remake but 3 others may be originals.
I'm saying here that if you have an oldies format and you didn't grow up in the era or know the original versions you are not the wiser to hear the remake and you unknowingly could have 50% of your playlist not originals depending on where you got them from. And it's not your fault.
Artisan Radio who gives me shows he makes to run on my station has found out that even the sources he accesses the songs from that were supposedly originals...if it's major hits, the re-recordings are everywhere and you have to keep an eye out for it and you can only know by knowing the originals. I have now a disclaimer on my station that runs once an hour that everything heard here is the original hit as you heard it when it was on the radio back then, no re-records here. And a mention of the cheap CD compilations that are all remakes.
I hate most rerecordings. They are just simply garbage. I've ran into this problem a lot recently. Wish they would state if they are or not the original recordings.
As Mark states, I've been burned a few times with remakes, even though the recordings were purported to be the originals.
But sometimes, it's not so easy.
Each recording session in those days ended up with multiple takes of the same song. One would be chosen to release, but in many cases the others were kept. Over the years, these alternate takes have been released, adding to the overall confusion of what was the original.
Adding to all this is that quite often, a different take or a remix was put on an accompanying album, quite often in stereo.
Finally, some 'greatest hits' albums of that era had the original artist, not that far removed in time from those hits, rerecord them. I purchased an album from Paul Anka back then and thought for quite a while that what I was hearing was the original hits, but sadly they weren't.
I play mostly obscure music that no one would bother to rerecord, so it doesn't affect me as often as it might. I do do the occasional Top 20 for the week of xx.xx.xx, taken from the charts of then Top 40 Vancouver B.C. Canada radio stations, so I'll just have to be extra careful for those shows.
I should also mention that jazz re-recordings are exempt from my comments. Jazz is based on improvisation, and quite often you end up with what could be considered different songs, based on a single one. That's why, when I play jazz, the voice overs indicate the exact date that a song was recorded (if it's available), and where it was recorded.