There is no guarantee the data you find in RAM can be found in the ROM at all. I'd say most of the values stored in RAM will not be able to be found in the ROM unless it is buffered data, copied tables or some data like that. RAM is mostly used for variables, changing content, and buffers in general.
If you're lucky and the data in question did in fact come from the ROM, you can do some searching on the hex values. If that doesn't work, then you have no choice but to look at some code and try and decipher how it got to RAM and where it came from. You can start by placing some breakpoints on the RAM location in question in a debugger as a starting point to how that data got there. Then you work backwards to see where it came from.