Yep, all Ruger guns that can use the BX trigger has plastic housings as OEM trigger housings. And I got my Red triggered BX in the other day.
I had taken the OEM apart and polished all the innerds. Wow, what crappy castings.... At any rate, put it back together and in the gun and shot a few rounds.
It was better, but not really that much. BX was installed and it makes a world of difference. 3 pounds or under break, and the OEM after polishing was still 5 or 6.
worth the money, but I'd have rather just paid for the gun to have it installed already.....