It is the same as the Elmarit 28f2.8 III. It was just part of the 70 year kit that Leica put out in 1983 (1913-1983). IF you find a collector of this kit - it can bring a bit of a premium, but usually they go for the same price as the regular ones. Leica made 2500 M4P's with this engraving and it was set up with 1-500 cameras with a prefix of L-xxx, E-xxx, I-xxx, C-xxx and A-xxx.
Standard, chrome M4P's too.
The rare version is 10-12 of them were the engraver was paid "a bonus" and made a "mistake". They read 1813-1983 instead and are known as the Napoleonic M4P's. I dont think any lenses were so engraved though.