Paul,

Maybe yours is not a GSS 341?

The common Walbro pump I have used is not found in any OE application,
as far as I know. I have seen Denso pumps in the configuration you
describe and picture, but the Walbros I have used look like the below
(note visible gears on inlet of the middle pump):

-Chris

Well the proof is in the suction test. If it sucks well it is probably
gears or rotors if it don't it probably is the peripheral
type. There is no need for the pos. displacement type if the pump
is in the tank.

Paul Lamar