I say fancy plecos because you're thinking of buying an L168, i.e. an expensive rarer pleco and in my opinion also a very attractive one. Any pleco you are thinking of would have to be able to handle an alkaline pH easily to be healthy. So you could look at the recommended pH range for a pleco species you're interested in on Planet catfish or similar websites and see if its able to handle it. I mentioned flash plecos because they are a species I've heard can handle alkaline pH's, and Geoff has had no problems with flash plecos at a higher pH. I agree that any pleco you get should be healthy in your tank and its an expensive lesson if its dies. You could always set up another tank with a lower pH, heaps of cover (bogwood, rocks, etc), good water flow, and high aeration for an L168 or two :lol:.
To my knowledge the L168's that were imported recently and are being sold as 'Peckoltia pulcher', L168, are the real deal, i.e. Dekeyseria brachyurus. There have also been the similar Dekeyseria sp. L052's imported slightly earlier. They are somewhat duller in colour but otherwise similar, and they were also a bit cheaper. If you worried about sexing them then you may be after more than one, in which case I'd go for a new setup :lol: They are difficult to sex but there are a few hints on Planet catfish.