In my humble opinion, it doesn't look suspicious. It looks like it's been used for a while, so the blue finish is a bit faded. You may have a look on my Western G46-8, which wasn't used anymore:   Also, you may see all my pictures for your reference:   

Yes, it's a head scratcher. It's not military production.  One wild thought is that it may have been made as a replacement at the unit level as a small contract with a local saddle maker. I can't remember any short sword with a narrow blade that would be paired with it. Great curiosity! Marv

The original finish on the blade was a beautiful deep blue. (I call it a Colt blue).  This blade looks a bit splotchy, which would indicate that at the very least, it was "touched up" a bit with cold blue.  If it were untouched, and had been used as expected, you would see finish loss on the blade which would come from honest use. Marv

From your description, it would indicate that you have a Turkish M5. Many have been imported over the last few years. Marv

Actually there is nothing to indicate that this M7 is a commercial version Imperial.  The curved runnout was introduced by Imperial in 1974 and continued through subsequent contracts through the 1984 contract. This M7 should also have a solid tang rather than the elongated slots found on the earlier models. Tim, if you took off the grips you can verify if it has a solid tang or not. The scabbard is as byf41 stated. Marv

Of the 33rd Infantry Division.

Thanks to everyone for the help 

Thats a mid to late 1970's commercial M7 bayonet and late WWII sheath for the M3 or M4 . It should fit youre M7 as well . 

Tonomachi maybe the oval in OP since it is ME is for that jump unit in the 8th Div, but it wouldn't be the whole battalion as you know that wore it, for those who don't know it just A Company (Abn), A Co supports those two infantry  and assorted jump units that made up the division's 1st Brigade, 1st Brigade (Airborne), this brigade goes off jump status in 1973, so plausibly this merrowed edge one he's got could of been worn in the very late 60s up till 1973.   There are several "12th Airborne Engineer Ovals up on the Bay for those interested.

Are these WW2 or Post War?