There are two copies of the RNA genome in lentiviral vectors. Measurements of viral particles, whether by RNA or p24, may not correlate very well with vector titer though. It's best to get a titer by actually transducing cells and assaying with flow cytometry or qPCR targeting vector integration into cellular DNA.
You can find many procedures online for titering lentivirus. I could provide some links if you'd like.
I am not worried about the titration, I just would like to know for sure that produced pseudotyped lentiviruses also have 2 RNA copies like wild type one.