well, the RG is a low priced jem like a volkswagon is a low priced porsche,
The RG and the Jem share the same body shape, but that's where it ends basically. With the exception of the edge tremolo's on the higher end RG's and Jem's.
The Jem of course has the obvious differences visually with the monkey grip and lions claw, and typically the different inlays, but also the neck profile is different, the neck width, scalloped frets, electronics, and in many cases the fit and finish.
However, if you don't care about the neck and pickups, then yeah, I guess you could call it a low end Jem, like you could call a beetle a low end 911.
A RG is a Jem with less horsepower and lower end handling LOL
You can argue the same thing with the RG7's vs Universe, but just like the Jems, there are differences.
I posted in a thread about the cost difference's, but I'll do it again,
Lets be realistic and assume that you want a Jem, vs the RG, but you buy an RG thinking you can convert it.
So, lets assume an RG550 used from ebay, for $350 compared to a JEM777DY from ebay for $750, both realistic prices.
Ok, first of all, lets make the RG functionally the same as the jem, ignore the cosmetics for now.
RG @ $350
new dimarzio pickups $180
Upper fret scallop $30
Neck joint modification (assuming the DY vs older RG orinal neck) $50
Body refinish from the neck joint. $150
Ok, now we have a total of $770 into the RG. lets add cosmetics,
Vine inlay or pyramid inlay $400
Monkey grip and lions claw $140
Jem style input jack $40
now we'll add those to the RG, $1350, the price of a new VWH!!!!!!!!!! and, the VWH is alder, with a lo-pro trem.
So, maybe that's a far fetched approach, there are lots that change the pickups in a Jem too, but, even with all those mods, you still have a wizard neck vs a jem neck, if you like that, fine. But basically, the bottom line here is, you can't compare a Jem to a RG, same as you can't compare a Porsche to a VW.