It could have been made up to replace the original that broke off during a repair.
Personally I prefer the original tag still there (even though they can be moved from trans to trans) as it "should" give an indication of the type of trans you are looking at - what variant, what gear combo, etc. If the plan is to fully rebuild or upgrade then it really doesn't matter.
As far as price, sure, if no tag I would want to pay less.