I'll give you the rundown of what needs to be done. yes it looks like you'll have to change injectors to the newer style.If possible buy USED injectors at the Junkyard or ebay
If you have no choice but to buy remanufactured then do it. It just cheaper to buy used.
NO, you do not have to recalibrate your injection pump, but you DO have to calibrate your injectors
ONCE you acquire your injectors, you have to get new nozzles because either:
A: the old ones are worn beyond repair
Or
B: Although brand new, they are made in India injectors, come with India nozzles and no matter how much anyone tries to tune them they have poor spray pattern. Period.
This is where installing new nozzles comes in to remedy this problem.
So you'll have to buy the ITALIAN MADE nozzles here.
https://www.idparts.com/bosio-sd265-injector-nozzle-om616-om617-om601-om602-om603-p-3084.html
And don't forget to use new crush washers
https://www.idparts.com/injector-heat-shield-ring-om616-om606-om617-om602-om603-p-3118.html?osCsid=d35693e8dd71a1cfd1e19cdc070c6ca3
Once you have your nozzles AND injectors in hand send them BOTH here to be pop tested and calibrated.
https://dieselfuelinjector.guru/
They have to calibrated and pop tested before you install them, even if you buy them manufactured.
Once they come back, they will finally be ready for installation.
But before you install them you will need new injector hardlines, because the slanted injectors sit differently, at least I imagine that would be the case.
That's it really.