all i know is that my og 18 from fem seed got TALL in flower. this b*tch wants to kill itself... it just stretches and stretches forever until it starts to bud. my buddy has this same plant since i cut him a couple clones of it. he has an original OGK too. only major difference is that the 18 is easier to get to multi-top. slightly less apically dominant. otherwise pretty much the same super stretchy strain.
the one i have in flower atm has some bleaching due to it stretching so fast on me, and my own error. like one person said tho, its got those spear shaped, super dark green leaves when its healthy. u can see the chem 91 in it for sure imo. ive grown other OGKs that werent quite so stretchy and tall.
and to whoever said how can OGK be airy??? its not hard. the other OGKs that were less stretchy had MUCH harder, denser nuggets in the end. in fact my buddy's OGK i speak of is quite a bit more airy than the dinachem he just grew right along with it, and a ton of others. the 18's buds are very similar to the original OGK so far.
in respect to the OP's topic in the 1'st post... yeah RP/DNA's OGK/OG 18 seem to be the most stretchy OGK's ive seen in person so far. the quality of the smoke is right on though... taste and all. the dinachem i mentioned has a very similar taste and high, but the nugs are way bigger and more dense. i didnt expect that. ive grown dinafem's ogk too. it was fire bud, dense, less stretchy, but RP's tasted/smelled stronger and better. i think i read dinafem's is an "Emerald OG"
the high, the taste, the smell... 10/10 on the RP/DNA OGK tho. so idk about them losing the original or anything... just a lanky one.