oy vey. yea if youre fuel injected then the filter shoulda been on the rali right before the tank. so the previous owner deffinately deleted the fuel filter.
if you have the experience and feel confident and are thoroughly versed in splicing fuel lines then go forth and splice away

. if not, then take it to the mechanic. cuz you really should have some sort of filter on there.
just make sure you know what youre doing, those are high pressure lines. but if you do it yourself it shouldnt take that long, mazybe an hour.
if you need advise on splicing the line yourself dont be afraid to ask someone. i'd give you more, but when my stock lines sprung a leak last winter i just took it to the mechanic. (they were just complete crap from stem to stern and it was 10 degrees out lol. i caved)