Some information for you.
1803 - Older non-quickset.
18038 - is a single-quickset up to 1988.
18238 - Double quickset released in 1988.
118238 - Released in 2000 i think... minor updates and according to TRF members, Later iterations of the 118238 - post 2002? got a heavier bracelet (no more voids?)
Anyway, I own a 1986 18038 .... When I was hunting used market for them, the pricing was approximately like this: (I'm not including specialty dials / diamonds / Stone Dials etc)
1803 - Head Only ~ $6k
1803 - W/Bracelet ~ $9k
18038 - W/Bracelet ~10-12k
18238 - W/Bracelet ~12-14k
118238 - W/bracelet ~16k+
I opted for the 18038.
To be clear on the technical issues around "Quickset".
1803 - None. You have to set the day and date by rolling the 24 hr or by rolling backwards.
18038 - Single Quick. Date is Quickset - 1-31. DAY is not. You have to roll backwards or forward to set the day then quickset the date.
18238 - Double-Quick. Date and Day are quickset.
Good luck on your hunt!