FN PBR was the hybrid control round/push feed action (sliding plate extractor), it came only in .308 and with the four round DBM magazine and black Hogue stock.
The FN PBR-XP has the classic, control round feed action with claw extractor. These came with a green Hogue stock, fluted barrels and were available in .300 WSM as well. .308s only with DBM, .300 WSM hinged floorplate magazine only.
Later the PBR-XP was replaced by the FN TSR-XP. These were the same as the PBR-XP but were made in FN's plant in Columbia instead of USRAC and these also have the Winchester MOA trigger instead of the PBRs which had the classic two-lever trigger.
Hope this helps.
AG