Welcome to AAPK. The knife looks like a pattern 62025-1/2, with rough black handles. If so it should be 3 inches closed length. The knife has what is called a “Tested block letter” shield, which in my experience is fairly common for Tested era knives having rough black handles. Your knife is what is called a “barehead” jack because it does not have a bottom, or end, bolster. Case made the same basic knife with bottom bolster, which is a 6225-1/2. The zero in the middle of the pattern number denotes a variation (in this case the lack of a bottom bolster) from the normal pattern.
Just a semi-educated guess for what it’s worth (not much

) is the knife was probably made about the time of WWII. Some believe the rough black (synthetic imitation jigged bone) was used during that time because of difficulty obtaining genuine bone. Also the bolster could have been eliminated due to shortage of materials needed to make nickel silver used to make bolsters. This is all hypothetical however. There are no known factory or catalog records to verify.
Nice find!
Ken