Drill hole on receiver ring of M'1917 ??

I recently bought a Reminton M'17 in excellent order; all matching. However, one thing stood out, which basically spolied the originality of the rifle. Someone had taken a drill on the receiver ring and hence a crecent shape had been drilled off, taking the letter M from the word 'Model'. Basically, what left is the word 'ODEL'.

The reason I am making a thread about this is because I have seen two other M'17 in the past with the same drill hole on the top of the receiver ring. If the hole had been complete i would have assumed it was for a scope mount. But in this case the drilling seems to have served no purpose other than take a bite off the ring :confused: I would imagine a pic would speak a thousand words. Will try to get one.

I look forward to your opinions.

Ah, after a little bit of searching found the answer in this thread:lol:

M1917 notched receiver