Winchester 1917 Bolt markings

[cherokee5425]

I have a Winchester 1917 s/n 475324 with barrel Date 10-18. However there is a number stamped on the bolt root # 43301.
Could someone tell me why the bolt is stamped with a number? BTW it is a Winchester bolt. Thanks in advance.

[Chuckindenver]

likely a lend lease gun, other countries stamped the serial on the bolt, common for bolts to get mixed up during reimport back to the USA

[cherokee5425]

Thank you!