What are the locations of all the numbers? I guess I never noticed more than one.
I bought 2 matching drums for $80 each shipped a few weeks ago.

I’d add 20% or more if the cover matches the drum body.
What I want to see is the serial number on the drum body, the flat spring housing, and the bullet platter all match. These parts mate and wear together and are more important to me than the matching top cover number.
As long as those three numbers match, that’s what I’m looking for, and of course condition, condition, condition.
As far as value, I wouldn’t take a penny less than $100 each for my excellent condition, all for matching numbers drums.
Words mean things, and numbers matching means exactly what it says. ALL numbers must match.
A 1963 split window Corvette would be a fun driver but without a matching engine, but it’s not worth as much. It all depends on what you’re looking for.
After examining, cleaning, repairing, in excess of 1,000 drums, it’s a pretty safe bet to assume most drums with a matching body and cover will also have matching spring housing and platter numbers.
I could assemble a drum with four different numbers and it would run perfectly. I don’t make the rules, but my experience shows true numbers matching drum sells for more the Armory Depot rebuilt miss matched drums.
My car would be worth easily double it's value with a 2.7T swapped in vs the 3.0 in it.