You are 100% right I came across that problem myself changed everything else on the bike because in my mind I had put a new pump in it I run high test fuel with octane booster me but the seal that was put in was brand new the old seal I put with the new pump and problem fixedI put mine in and still had a fuel pressure problem, It wouldn't hold pressure. I tracked it down to thew pump seals in side the LTR housing. There is a seal that goes on the outlet of the pump and an Oring that goes on the white plastic end cap that seals to the housing. Both of mine where dried up and wouldn't seal %100.
This is probably because I run %100 AVgas and over a long period of time it seems to dry out rubber and plastic components. I did have two other used pumps that I purchased on the HQ that have not been run with AVgas and the seals where dried and shrunk as well but they have been sitting out for at least 4 years.
Just my 2 on what I found,
the New pump dead heads at 80 psi. and holds pressure just fine now.