GMC Suburban Trim Level Q?:

[special-K]

I've been sorting out how the pickup trim leves went on 67-72s and it brought me to wondering about the same on Suburbans. I know that top-of-the-line Suburbans were 67-70 Customs and 71-72 Custom Deluxes. What about GMCs? I figured they were trimmed the same as Chevys,right? Well,does that mean the top trim was Custom,except '72 when Super Custom became the equivalent to Chevy Custom Deluxe (on pickups)? On GMC pickups,prior to '72,the top trim level was Super Custom...same as Chevy CST. I know starting in '69 the Sierra and Sierra Grande came out,but through '71 those were option packages on top of whatever trim level...like the Highlander pkg. I guess the question here is am I wrong in thinking I've seen Super Custom Suburbans prior to '72? Were they all Customs through '71? Were there Super Customs but,unlike the pickups,they were mid-level trim? Or,because there were no Sierras (& Grandes) in Suburbans,was Super Custom equal the Custom Deluxe ('71) and Custom before that?