If you can replace it for free, then it is a MAYBE. If you need to pay money for it and 811 is working fine like you said, i would say NO.
My guess is that PUH on 811s may not be best design/quality, that is why LiteOn switch to 851 and continue to use same hardware on 812s. Either that or LiteOn try to save money if new PUH is cheaper to make. Remember, 811s is same hardware as 401/411 which were rushed to come out back then cause they were behind other competitors. Also, if history taught us anything, newer generation drive from LiteOn tends to be better than older generation anyway.