if im not wrong, the older scotty camerons came only in 35inches, with 330g headweight.
the studio select models come in 33, 34 and 35 inches, with 360g, 350g and 340g respectively. I'm assuming that the select models follow this configuration
if so, then yes, the headweight of your select is 10g heavier than your studio design
in addition, depending on the condition of your studio design eg whether it has been refinished or not, the headweight may be further reduced.
finally, check also if your current grip on ur studio design is the stock studio design grip. the stock grip is very light which will give the putter a heavier swing weight. if u'v changed the grip to a heavier one, then it will feel even lighter
hope it helps