Hello Vincent,
There is a good break-down of the different injection pumps on page 07-0/3 of the BBB (factory workshop manual). This information is also a "July 1973" supplement to the manual, so unless your manual is up-to-date with all the supplements, you may not have it. According to this supplement, the "R-24W" was used on 280SL/8 with Sweden exhaust emission control year of manufacture 1971, as of engine number 005 302. The "R23" injection pump was fitted on 280SL/8 and 300SEL/8 cars. The test output values for setting up the two pumps is different. Most likely the R24W is set-up different to meet the Sweden emissions regulations. I suspect either would work on an M130 engine, the R23 may provide a bit more power than the other?