I used to use the original Galerie. If the Galerie you have is this version, then, yes, the matte base is noticeably warmer than the glossy. A new version of Galerie was introduced, sometime during the 90s I think, and I've heard it is a rather different paper. The original Galerie was a very beautiful paper, both the glossy surface (remarkably deep blacks) and the matte.
BTW, speaking of old paper, I recently started using a long lost box of the original Ilford Multigrade FB, purchased 1988. Despite 18 years of Tokyo summers, it still has excellent contrast and speed, and no obvious fogging. I nearly threw it out, assumed it would be no good.