I would suggest putting it at the end of Program Memory.

The 1503 has 2K words of flash, so two locations starting at 07FEh.
It will store the lowbyte and highbyte separately.



Code:
Temp   VAR WORD
Seed   VAR WORD

READCODE $7FE, Temp
Seed.LowByte = Temp.LowByte
READCODE $7FF, Temp
Seed.HighByte = Temp.LowByte
I don't have access to a 1503 today, but I think it should work.