My knowledge of car cement is limited to a few box cars I used to walk
by almost everyday. The ends had car cement on them, although I didn't
know that at the time, the ends were black. The cars were all
refurbished and received solid bcr color paint, but you could still
see the texture of the cement on the ends. The best way to describe
the stuff is to say it was like roofing tar or more like `Black Jack'.
I doubt if the texture would be worth modeling in HO. Of course, I
don't add rivets or add up those itty bitty numbers :)