Pipewelder is right in that it is not required by Section IX to use a stainless steel base metal for qualification with a stainless steel filler metal. However, QW-301.2 does require that the welder use a qualified weld procedure, so the contractor needs to have qualified the F#/P# combination before a welder can qualify with it.
Swah,
My opinion is that you are right to question the Contract Welders abilities.
I've been in your same situation a few times and, if the situation was not carefully controlled, the "Contractor" would send out only one or two welders (if I was lucky) who actually knew what they were doing and the remainder would be dead heads who claim to be able to weld anything just to get out on the rig because they know they are getting paid well, even if they get sent home.
I've also been on the other side of the situstion where Welders form my shop had to go out to someone elses rig to make repairs.
The best way I found to handle the situation is to first have an ABS Surveyor review and approve the repair/addition plans and job specific WPS's. Then I would have the contracted welders perform a qualification test, witnessed by the ABS Surveyor, prior to being sent to the job site. That way, anyone who can't pass the test doesn't waste your time.
Of course there are different circumstances in every job concernig time, money and contract restraints, but if you don't stand your ground you'll get pushed around. The argument that I used to justify the extra time and expense to was that if you take steps to ensure the best probability of acceptable welds before you start, you most likely won't have to go through the greater time and expense costs later of the nightmarish repairs process. Also we made the Contractor eat the cost of the WPQ's as a way to prove that he can supply qualified welders.
Good Luck and be safe out there!
Tim