Based on your description, I would think it is from the last (and most desirable) generation of 4506.

The BDK prefix would most likely be a 2006 product. A 4046TSW BDH9851 was dated by SW as 7/2005 and I have a 5946TSW dated by SW as 3/2006 and all (12) box ends I have seen with BDK prefix have 6xxx Codes. Easiest way to date is to email complete info to SW at [email protected] - they normally respond M-F only. And if you ask for 6 digit Product Code which might give you a clue to provenance, you may or may not get it depending on who responds.

As to magazines, as I recall, the first 4506 had orange followers and after reported feed problems on some pistols, the internal geometry and the mags were tweaked to the 4506-1 configuration to address the problem. The new 4506-1 mags had yellow followers and most were marked "for 4506-1 only" as well as "must have yellow follower". There were still some feed issues and the mags further evolved to the black follower with no use restrictions.

The 4516 had similar issues. .45acp Magazines

Based on the configuration and presumed date, I would assume the correct mags would be the late mags with the black follower.

Others have reported no problems mixing and matching mags in the various 4506 configurations with no problems, but personally I would try to secure some more late mags with black followers and reserve the ones with yellow followers for range use.

With respect to price, condition, box, correct mags, location, and provenance would all add value while sellers knowledge and length of time on the market would potentially decrease value. I would not count the "incorrect" mags for much but "correct" mags go for $50+.

Local avoids shipping and Private Party probably avoids sales tax. For $600-700 out the door I would grab it. For $800+ it would stay where you found it. But thats just me - if you want it, make an offer.