Spending this weekend finally installing the front end kit i bought last summer, I noticed my springs are BUK code. This was on a printed paper label around one of the springs. It also had the part number but I dont have it with me. gmpartsdirect and my local dealer couldn't tell me anything about them, and none of the spring charts i've seen here have them in it? Any ideas? could they be from something other then a thirdgen possibly?