i think there's a good chance they would. if you think it would help (which i think it might) you could always stretch the truth and say that you have a possibility for a job this fall, and that you would like to be considered as waitlist for the PT program. if they allowed that, you would probably get in without a problem. and it wouldn't hurt to try- worst case scenario you stay where you are on the FT waitlist.
i entered GW PT and transferred to FT this semester. out of the 120 people who started PT, about half switched to FT after the first semester. a lot of people decide they can't take working and going to school for 4 years, and others enter with no job at all, intending to switch from the beginning.
as far as it being "good", i can't entirely say. as far as i can honestly tell (from talking to upper-level students, guidance counsellers, professors, etc.), it doesn't have as much as a negative effect as most people would think. people who started PT and switched to FT still get plenty of jobs at OCI, clerkships, good summer internships, etc. i was in a position similar to yours- my choice was between GW PT and a school ranked somewhere around where OU is. at first i was hesitant to go PT, but now i'm happy i did. even though some people on these law school message boards might give you crap for using the "backdoor" in to a T20 school, that's about as bad as it gets. you'll still have your own section (with other people who switch to FT) with whom you'll graduate in 3 years, just like those who start FT do with their sections; the only difference is that you'll be 2 classes behind after first semester and will have to take some credits over the summer (which is very easy and can be done in a variety of ways). and of course, when taking in to account the opportunities GW will offer you that a place like OU might not, i honestly think that alone is worth it.
but if you were waitlisted at GW, i'm assuming your numbers are fairly competetive. have you considered applying to GULC PT? i think they're still taking applications online until March 1, so you'd have to rush. still, their PT admit stats aren't much different from GW's, and while you can't switch until second year, it's also very easy to do and you'd be in an even better position than you would at GW.
let me know if you have any other questions.