Welcome to the Forum.
I can see from the photo it's a 1084S monitor, which is enough info for that.
For the A1200 Tower it would be useful to know what is inside, any storage devices, add ons like accelerators, memory expansions etc. pictures of the inside would help.
Is there any software, disks etc?
Have you turned it all on, do you know if it works?
Final question...would you regret selling it?