RGRxxx refers to a reverse headstock, *not* RGxxxR.
The letters after the numbers usually refer to finishes
IE RB (Royal Blue) or JB (Jewel Blue)
but in some cases there is first a code for materials or appointments:
IE VWH (Vine+WHite) PBK (Pyramids+Black)
or FAWN (Flamed Ash+Walnut)
or DXGSV (Deluxe+Green Silver)
or XTLB (Double Edge+Transparent Light Blue)
or if you are very lucky something like DNA (duh) or HAM (Hoshino Anniversary Model

)
loads of possibilities...but most of those won't be available on a 270
I happen to have thew 2001 and 2005 brochures here and no RG270R in those, there is however an RG270B (in JB or BKN) the B refers to Basswood. An educated guess: but presumably because there is/was also an RG270R in Agathis or Luthite (Resin not wood)