Rutger,
I just finished my 9th kit build. The hardest thing to find is the original "tool roll" material, but they are out there. The Gray/Green light canvas fabric is standard. I haven't seen any other, and no, that inside fabric never matches the interior bag color. The outside can be canvas from a soft top (black, brown, and olive green are common), or an array of seat material (typically MBtex). I have smooth light gray, smooth cognac, smooth red, textured tobacco brown, textured medium gray, textured tan, textured red, and a black canvas one. I do have one repro bag in cognac, but I prefer to find the originals.
If you want authenticity, make sure she uses the short Hazet 767 spark plug wrench without the spring(that was 107)(don't forget the rubber insert), the original Heyco 300 long water pump pliers with the star (mercedes quit supplying the logo version recently, and the 107's came with smaller heyco pliers), the thick hapewe pliers (thin ones were 107), the mercedes wrenches, Felo plastic screwdriver with two inserts, fuse kit (with 4 stubby 25amp fuses and the rest 8a long white fuses (no red or blue), and black fuse pullers. I throw in the Hazet 2760 Oil service wrench that is in the special "Lubrication Kit", as well as both the 17mm/14mm heyco, unior, dowidat, or matador wrench (pre-1965 DIN895 change) and a walter 17mm/13mm (post change). I also include the wheel centering guide (one with slot, not the longer aluminum 107 type), and a Heyco 17mm Lug Wrench.
The four open end wrenches rarely came in matched sets from the same manufacturer, so a mish mash is authentic.
Some of the later kits had a black printed tri-star logo stenciled on the green/gray inside canvas (on the right side). These are more uncommon.
Hope this helps.
Mike Mizesko
Columbus, OH