Greetings Don.
I have an older, lx865, with similar, if not the same engine, i think. I have not personally replaced the lucas pump, but eventually i may, so i am very interested in your experience. The service manual for my machine says "(install gear)".
Not much help there. Skipping over to the lx985 section, the manual actually shows a locking bolt. ( I will scrape the gunk off & check next time i am with the machine, but it is 15 miles away right now)
Does the attached image from the lx985 service manual apply?
_let_me_stress_ i do not know what engine is in the 985, other than it is a 4 cylinder, nor do i know for sure that the 3cyl engine in my lx865 & service manual is a 330, thus you should verify your torque specs & sequences for your engine, make & model.
( you may already know this ...I was some what less than pleased to learn that i should not wash the outside of the fuel pump if it was even warm. The tolerances between the outer portion of the fuel system rotor & the inner portion are so tight that cooling the outer portion will shrink it onto the inner rotor, damaging these very expensive parts.)
Remember, if you have turned the fuel pump shaft, it may need to be re-timed. Good luck, & let us know how things work out.