6 unidentified RPO codes

I've decoded all RPO's but the following six using several resources (dealer and web bases tools). Can anybody shed light on these?

AXP
RYJ
R9U
6GK
7GK
SCM


thx in advance
-brad

(these are for 03' 2500 4x2 burb)

not sure what the last three items below mean, but i did find these except for the SCM code:

AXP MPV VIN IDENTIFICATION
RYJ RETRACTABLE CARGO AREA COVER
6GK SPRING COMPTR SELECT FRT LH
7GK SPRING COMPTR SELECT FRT RH
R9U CONTROL SALES ITEM #95

-brad