If the other release does not have enough information on it via edit notes, scans, or sources/external links for you to be able to tell for sure, then there's no harm in merging it - if you can't identify it properly then nobody else can either, which doesn't make for valuable database info.
If a user disagrees and knows more, making the merge edit is a good way of starting the discussion, and you can always cancel.
If you really want to double check, I would leave a note here, or try contact the original editor:
As you can tell, I definitely lean towards the 'merge' side when editing, a confusing database is a annoying database
edit: to preserve information/prevent future confusion you can put in the label twice if you want - once for each cat no.