Dating Rolex Oyster Perpetual 1956?

[Winger]

Hi all,

I have this Rolex and I am extremely confident it is real. The Serial number is worn off from all the years of wear. it is a long way from mint. there are some faint numbers still left to see, and somewhere along the wine the wrote the serial number on the inside of the watch back. 189,377. This number I can see the 1, 9 and last 7 in where the Serial number is, but so worn down its hard to make out. I am wondering if anyone can confirm the rest of the numbers on the inside that would validate the year. One Very strange thing is that 6584 is lined out and 6580 typed in the back. Also appears to have M54 stamped in the back of the case along with 18. Movement is 1030 and the inside number on the edge is 474720. Any help with these numbers would be appreciated.

Also, The fron has Oyster-Perpetual and Officially Certified with Chronometer under the certified. I think 1956 was the first year for Officially Certified?