I've ordered from them. Good service and prompt delivery. YMMV.
To answer your question I think you can swap the relief valves.
Got a decent deal on kegs but looks like they'll be selling only parts soon:
We have been liquidating Pepsi's used equipment since 1996.
In some years we liquidated over 60,000 kegs per year.
On 9/29/2009 we picked up the LAST 800 kegs in the Pepsi Corporate system in the Western U.S.
Pepsi (PBG) has no more kegs on the west coast.
An independent Pepsi Franchise plant will be making a keg release w/in 45 days.
There will be only 2,400 kegs released.
We will post kegs available when they are in transit to us.
There will be no more discounts on multiple kegs and no wholesale sales due to the
EXTREME SCARCITY of used kegs.