Yes... I've looked at some images and it does appear to be bottom color (light gray). Made a milestone today... got the front fuze halves joined. Before getting to that I added just one wiring detail to the nose wheel. The brake lines are already molded onto the G-force brass nose gear casting so I left it alone. If it was styrene, I might have scraped it off and added 3D detailing. But I had no desire to remove any brass. The line is the wiring harness going to the landing lights and Glide Slope Antenna. I just put on one wine bottle foil clamp to stabilize the wire.
Before gluing anything together, I needed to final fit the cockpit to the right fuze half. There was a large gap behind the bullet proof bulkhead behind the pilot's position, and, more importantly, there was a huge gap just in front of the cockpit.
You can see that the cockpit side panels are in close contact with the fuselage, so the cockpit is actually located correctly. But when sighting down inside the nose I saw that the rectangular lugs were impinging on the curved fuze sides as a result of the raising the cockpit height 1/8". I took it apart (held with masking tape and rubber bands), and flled the tops off the cockpit tub's lugs to chamfer them and have then nestle closer to the fuselage. This resulted in closing the gap about half the distance.
This gap was manageable and, furthermore, didn't put the windscreen too out of position. With this problem sort of solved, I glued the tub to the right side holding it in the right position with masking tape. I then added the nose gear. The tub was held with medium CA and the nose well with Testor's tube cement.
The tricky part was to get the tub lugs on this exposed side to drop on top of the sockets in the left fuze half. I practiced doing this before any gluing was attempted and before the nose wheel was in place so I could visualize what was going on. I put thick CA on the tub and plastic cement on the wheel well and put the two halves together. When possible I put liquid cement on the inside of the joint, but otherwise, I used a fine brush to apply it on the junction from the outside. Had a couple of drips that are okay as long as you don't touch them befor they cure.
I used thick CA and then Bondic to attempt close up the front gap.
During filing the plug came out, so I went to plan B, fill with styrene. Notice on the image below that I opened the sheet metal holes in the gun compartment. There will be some wiring coming out of those too.
After dinner I went down and trimmed the filler piece. Still needs some work but it will be fine.
That's where I ended today. I want it to dry completely before doing any other filling and trimming. It is one BIG airplane.
I also did some photo research and found that the yellow gasketing on F-105G cockpits appears to be hit or miss. This pic shows basically no gasketing.
And on this one, it shows gasketing on the windscreen and front cockpit, but none on the rear.
So whether I put gasketing on all, one or none of the glazing is my choice and I guess based upon the actual plane that I'm modeling. I have the yellow tape to do the job and will start with the windscreen. If it works okay, then I decide on whether to do the rest.