Reproduction pushbuttons are available here:
http://www.renovatedradios.com/parts.html#pushbuttons
There are a number of RCA radios that use similar bezels. The difference is that the TRK-5 bezel uses aluminum pieces around the eye tube and electric tuning light, while the bezels from other RCA radios either have no pieces or have pieces that are silver. It is easy to remove the painted pieces from the old bezel and put them on the replacement bezel, though.
Here are some of the RCA radios with similar bezels:
98T, chassis RC-386A
98K2, chassis RC-386A
97K2, chassis RC-351K
97T2, chassis RC-351K
96E2, chassis RC-351L
96K5, chassis RC-351L
96T7, chassis RC-351L