I'm afraid I never bought a lift pump or replaced my lift pump gasket in my 2003-ISC-350-CAPS engine, because I fixed my air in the fuel line problems by simply tightening my 3-lift pump bolts (#6 in the diagram below).
However, I saved this distributor's information on CAPS lift pumps for future reference, but as "OldScout" implied, I too am under the impression there were different types of gaskets for pre-2002 ISC/ISL motors, so this is one of those cases where you need to find out what the latest part numbers are.
When you find out the latest information, please post for the rest of us! ...And while I'm guessing you want to talk to Cummins... maybe you need to call your chassis manufacture for a part number update and price.
Here's a reference to an aftermarket lift pump I think is every bit as good as the one Cummins sells for twice the price:
Note: MD Distributors is a large a reputable company with their own Turbo rebuild shops. They have many locations and I don't think they sell anything they have not qualified. They service the Semi-truck market mostly, but they have inventory on a lot of Cummins engine parts.
Here's some information I captured off the MD Distributors website above...
Engine(s): 8.3L ISC C-Series & ISL
CPL #(s): 2691, 2692, 2693, 2694,
2695, 2964, 8106, 8158
Manufacturer: FP Diesel
Use with: CAPS Fuel System
CAPS: Cummins Accumulator Pump System
Voltage: 12 Volt
Includes: 2 Threaded Plugs
Not Included: O-Rings &
for Install Kit)
Install Kit: 4935005-INS
Install Note: Install Kit contains all
O-Rings & Sealing
Washers required to
install this pump for
Pump Note: Older 8-Port Style Pump
bases will need 1 each of these plugs 3040815 & 3046202
Plugs: 3040815, 3046202, MFL-2408-06, MFL-2408-08
===> Another thing you can do for us is this: When you take apart your lift pump, please let us know if you come across the #10 check-valve sitting on top-center of the lift pump; or if you see it in the Lift Pump Manifold body as drawn in the diagram below. Thx.