I wouldn't pay that much for it.
Hoten bayonet is a good one, one of the rarer ones and alone can sell for $200 in good condition and has the scabbard. Slings are also rare if original and condition can make a huge difference here as well. Original dust covers usually have serial numbers on them but doesn't seem likely a rifle picked up in 1946 would still have one, most were discarded early so could easily be one a previous owner put on it. Capture papers are a plus, how much depends on the buyer. Kokura is one of the most common rifle manufacturers so nothing special there, same with the series #. Surface rust takes it out of the better conditions also. Kokura arsenal was one that used assembly numbers so the bolt may actually be matching based on that. You don't mention if the mum is intact or not. That can be a $100 difference right there.
Too many variables to value it at $1000 without a lot more information. Basic rifle without mum in average condition $300, with mum +100, sling +100 or more, papers +100 (maybe), bayonet +150, bolt matches assembly number +100, dust cover a wash without matching serial number. And all these estimates can go up or down depending on actual condition.
I'm still seeing Type 38's sell for under $300, Hoten bayonets for around $100. I don't see either original slings or papers come up that often.