Nice! That's about 13 serial numbers away from mine. Pretty sure it's 1922. Now, what's it worth? I have a Nickel one (yet a 1928) listed right now for $8000. I had a brass lacquered 1924 Buescher Bass for $5K and I had them beating down my door.
Conn basses are rare, yet recently there have been a number popping up. Bueschers are in a different bracket. The price pyramid of Conn's (Which in my opinion are a better bass) are (not counting the one's to F), Bare brass, first lacquer (as back then they never lacquered), Nickel, Silver with Gold bell, then gold plate. Condition is everything.
Playability is more of everything. Price of reconditioning is everything. I am in the middle of my silver one and it's taking lots of time. I agree $5000 for an overhaul is high, but it is labor intensive to clean all that silver let alone pad. I think I charge $2500 ish before cleaning.
Again now what is it worth? I hate putting prices on stuff!! I think it comes down to how quick you want to move it. Your condition (from what I can see in the pics) is not great. I'd say $4K to $7K MAYBE. If it was all finished and in mint playing condition, I could see someone paying $10K, but you might have to wait awhile. BTW take some pics and visit and submit it to
www.Connsortia.com. While you're there look around, it's worth the time. Good Luck!!