This is an old thread, I guess, but thought I'd throw in some notes:
I have some late BLP Liberty monos. They're kind of fun to collect because they're affordable and still a bit rare.
I think that Grant Green's BLP 4253 is the first mono that exists only as Liberty pressing (has no New York, USA label counterpart), so that's where I started my collecting for this series.
The last-ish ones that I have are:
BLP4273 Hank Mobley Hi Voltage
BLP4274 Tyrone Washington Natural Essence
BLP4277 Horace Silver Serenade to a Soul Sister
I have never seen a mono pressing beyond 4277, but I guess that website suggests there are...my quest continues!
On my copies, the pressings are typical lame Liberty (less vinyl mass, poorer print quality on the labels) but the mixes are still good, especially if they are Van Gelder.