Early Mod 1904 Caliber 52/53 With Snail Style Micro-Regulator

I've enjoyed reading the posts here! I have the watch movement described in the Subject and I'm looking for a micro-regulator spring and mounting screw for it. I believe the parts are interchangeable between the early Mod. 1904 Cal 52 & Cal 53 snail style regulator. Please advise whether these replacement parts are available. Thank you!

Dave

You might try searching "IWC CAL. 52u. 53 H6 Lep. 19''' LINIG RESTLESS CLOBS WITH FINE ADJUSTMENT PART No. 121" on a popular online auction site. That was the description for this:

No tiny detail that will not be answered. I'm flashed!