Yes, a small amount of spindle showing on the drive side between the bearing face and spider in a GXP system is normal. In order to achieve proper chain line, there will be a small amount of spindle showing between the bearing face and the spider in a GXP system.
How GXP works: You’ll notice that the crank spindle is stepped at the non-drive side interface. The step is designed to bottom out on the inner portion of the non-drive side bearing. This way, the system properly centers itself in the shell, giving you proper chain line on the drive side. You’ll also notice the location of the bearing race (the shiny polished portion- where the drive side bearing sits on the spindle) is slightly inboard of the junction of the spider and spindle, giving room for the proper chain line of the crank.
Always be sure you install both GXP cups before trying to test fit your crankset. If you do not install both bearings, the crankset will not be aligned properly in your frame. Your drive side may contact your chain stay in error.