Try posting on the 03/03A3 Forum at www.gunandknife.com.
Describe the rifle in detail, including receiver markings, barrel markings, stock cartouche and any other stock markings, grooved or ungrooved stock, buttplate (smooth or checked), etc.
The folks on that forum are very knowlegeable and will help you. If all original, that rifle would run well over $500, in spite of being low number. FWIW, I don't recommend shooting low numbers.