If you haven't already, don't bother with an OEM replacement part. It's made from stamped steel, and rusts out (as you've noted...)
Go to the hardware store, get a brass pipe nipple in 3/8". You can use a straight nipple a few inches long and just cut one threaded end off (you don't need threads for a hose join,) or figure lengths and get a long nipple, an elbow, and a short nipple to eliminate the moulded hose join (I don't know the lengths offhand, but I know it can be done off the rack at the hardware store.) Brass is recommended - it will hold up much longer.
The thumb rule for a 3/8" NPT join is to go one-half turn past finger tight (using PTFE sealant,) and then tighten to align (if necessary. If you don't do the elbow, you won't need to align.)
Even getting a galvanised iron nipple will cost less than the dealer - and last longer.