I think it's a Prussian M 1839 or Belgian copy (doesn't look like it's been converted); about .70 caliber; rifled barrel is 32"; overall length is about 48"; stock has a faint stamp with a crown over W in the center/1845 on the bottom; barrel has 1845 and crown over LF; right sideplate stamped with a crown over AB/over 45; hammer and butt plate both stamped 504 (butt plate also stamped 1845); stock under buttplate looks to be stamped AB; double folding rear sight is stamped JR on right side and a crown over what looks what looks like "18" on the left side. There are numerous other small crown stamps all over (inluding on the nipple). I would guess the condition is Fine or VG overall. Could anyone give me any info, value, what to look for, reference source(s)?

Thanks.
CQ