I have a really nice Smith & Wesson model 645 in 45ACP. It is an incredibly rare pistol. For those who know Smith and Wesson's, this is a transitional model. It also comes with 8 mags!

 

 

Here is some additional information.

According to the Standard Catalog of Smith & Wesson (4th Edition), the transitional "6450" model (Product Code 103710), which features 3rd generation-style internals within a 645-marked frame, is often cited in collector circles as having only about 300 units released for commercial sale.
These specific transitional pistols were produced around 1988–1991, serving as a bridge between the 2nd Generation Model 645 and the 3rd Generation Model 4506.
 
Some collectors also refer to late-production 645s with mixed 3rd-generation parts as "transitional" or "interim" models, which were produced in limited numbers before the 4506 fully replaced the 645 in 1988.