Howdy
The CR prefix was used to denote a SS frame. Probably made by Cal Foster or Caspian(kinda the same) That gun is a higher serial number and should be a real good gun as it benifitted from allot of the continual improvements that went on in the factory. I have used the Essex frames for many guns that I built and had very good luck with them. I do like the Caspain better and use them for full size 1911 guns. These were all within the last 10 years or so. It's possible that the quality was lower in the past. For a carry gun I would reccomend one with the highest "CR" serial number you can find(probably the 20ks) still made in seattle. Stay away from the "New Detonics" stuff. The Detonics USA guns are outstanding. there is allot of usefull info on the Detonics page at Yahoo. http://groups.yahoo.com/group/DetonicsCollectors/
Check in the documents area. When compared to new guns of similar quality the old Detonics guns are a BARGAIN.
Hope this helps...
L8r
Conley Janssen
USMC 87-93