Thanks for the replies, it's helpful info.
1 - Yes, I meant Part 52 for the Matrix, rather than 53.
2 - In further review, I believe meteec hit it on the head. Some of the programs were under GSA schedules.
3 - If this is the case, that they are under GSA schedules, I will abide by the Ts and Cs of the schedule, also.
4 - Here is one, it's with NCUA. http://www.ncua.gov/about/Pages/RFP.aspx
5 - No clauses incorporated by reference. Or, if there are, there are very few, and generally agency specific.