Julien's Auction is putting some interesting guns from movies up for auction to be held on Nov. 20th. From the Golden Closet Archives catalog,
AMT .45 Longlside from Terminator is going on the block for $10,000-20,000 (p. 34 of catalog). Laser is not included, though
M16A1 with grenade launcher used in the last scene of Scarface(1983) by Al Pacino's character. The gun lacks firing pin, and the grenade launcher was custom made. The grenade launcher was also used in Predator(1987). Price is expected to be around $20,000 - 30,000.
According to jbntex from AR15.com, the serial number is 9310593, and was sold by the famous Stembridge Gun Works company.
There are some prop guns from other movies such as 'Salt' used by Angelina Jolie, CTU badge used by Keifer Sutherland in 24, pistols from 'Sopranos'
The catalog has far more costumes used by many shows as well. Bud's wrestling costume from 'Married...with childrens' is there too.
Auction catalog: http://www.juliensauctions.com/auctions/2015/golden-closet-archives/index.html