Thanks Gary. You may be correct. What we need is confirmation from somebody (or several somebodies) with a confirmed shape T bottle.
I think the deciding factor is whether the body of a bottle is fully hollow or if it has a small "well" below the neck and solid glass (with or without internal decoration) below the "well". If it is fully hollow, then I think it would be for scent. If it has a "well" section, it would be an inkwell.
I believe the criteria of "hollow or not" could, and should, be applied to any Moncrieff catalogue bottle of shapes: T, VB, WB, HE, IE, RE, PF, ZG, KH, SI and EJ.