Is yours a made in Monson Mass handgun and haveing only a 4 digit number might be from 1978. Blue finish right?? Sounds like it has a front site made by EWKarms and can be found on the danwessonforum. I have a 4" version made in monson mass. with the same grips with a serial number of 16xxx. To bad as you now have the DW revolver dezzzz. Now you have to watch for the centerfire models to add to your .22lr I also have a couple 357, 15-2 and a 44mag all with several barrels and grips.
Heres a couple pages for you to help understand them better
Here is a link to the danwessonforum pages and besure to read up in the arcives and history section. Sign up and spend some time here. It very hard to post put tight build dates to these handgun as there is NO original info from DW and the company changed ownership a few times .