Yes, shin-gunto mounts, but I think the saya is missing the ashi (hanger).
The tang has probably rusted itself into the wood of the tsuka (handle).
Removing it will be difficult. You might try CAREFULLY taking a block of
wood against the tsuba (guard) on the blade side and tapping it with a
wooden mallet. Obviously after removing the bamboo peg. Alternate sides (left/right) so as not to bend the tsuba. Be very careful as the blade is sharp and you don't want to miss and cut your hand off. Don't use metal tools on it as they will scratch and scar the tsuba, blade, etc.
Also look carefully that there are not TWO bamboo pegs (mekugi) - the one
at the base near the tsuba and maybe another near the top of the hilt. Not
common, but I've seen several mounted like that.
Rich
The Japanese Sword Index
http://www.geocities.com/alchemyst/nihonto.htm