The 1st one in to login into the collectors market here and to try some searches ... ie : write "Pam40" then click on "date" then click on "go", by a miracle you will see the last models of this watch for sale or sold, that should give you an idea about a potential value.
The 2nd is to post a " For sale " in the same collectors market, you have to state a price don't miss this rule
... if the watches are sold in a New-York minute that want to say the askings were OK or even very OK
, if you don't get any interest or contact : yeah !! prices are too high
Btw, well played !! you'd already get some offers in your inbox and the bids can start