Question on sec air pump

Im in the market for a newer blazer. i have a 98 and am not getting rid of it, ever! i was curious about the sec air pump and if it was available for both 4.3 v6 vin W and X. and i was also wondering if K18 is the rpo code for it. if its not K18 then what is the proper rpo for the sec air pump is. tryin to stay away from a blazer with sec air pump. just a prefrence i have.

You are correct about RPO K18. If that code is included in the RPO code list, the vehicle is equipped with the Air Injection Reactor, (AIR) system. The "X" engine code indicates that the fuel injectors are located at the intake ports. The "W" engine code uses a centrally located single injector on 1995 and older engines. 1996 and newer "W" engines use 6 mini injectors centrally located in the plenum. The AIR system was used on certain, (not all) "W" and "X" engines starting in 1999.