Thats exactly what I am saying.
The year matters I know for a fact that at least 98's and 99's(not sure about what portion of those years) do not have external regulators on the assembly. The pumps on those years are internally regulated, which means if you put in a pump that has a built in 100psi relief will run 100 psi and all the new internal aftermarket walbro pumps have that 100psi relief.
You bring up an interesting issue, but, there is a problem. Mine (97) is a rock solid 55 psi, there is a post above with a 2001 that is also working without a return. I also know of a 98, 99 and 00 , all with the Walbro. When i pulled mine I was convinced the old pump had a built in regulator, but, as i investigated further, it appears the regulator is built into the bottle fittings. I have the old pump, if I have some time i will pressurize it and try to see what value i get.