Yes armor is not that weighty. But again if you want to House Rule something that is fine if it fits your game. Such as an advanced race (or not advanced) using some exotic material that cannot be replicated scientifically that reduces the armor mass.
IMHO you can/should use the rules in RM for armor fitting and superior armor. So I guess this would allow for some reduced in weight but at the high cost of tailoring your armor. I might say as much as x2 to x20 depending on type of armor.
MDC