I have a 2245 set and wanted to paint the aprons the same red color as well as do touch-ups. I spent a lot of time mixing paints to come up with something that was a good match. No luck. I then ordered a can of paint from Charlie Wood and.....it didn't match. I think that this is the problem......these shells are 60 years old and a lot happens to paint in that time. As new looking as my shells were, they didn't match the color. So, I think you either repaint all of it or leave it as is. Or.....find other sources of TS paint and try them. Piecemeal isn't likely to work with red.
Roger