Sublte, I have re-used the Main Bearing Ladder bolts three times without any problem except Will breaking stuff flogging the beast !!!!!
Other then that the oil pump chain is loose on all of them so replacement is just a waste of cash.
Of course this is some work but if you bought the update kit I think your going to come out ahead in the long run. Especially getting to change the rear output bearings to the newer style. and you even get to see if the bloke drank to much ale for lunch when they assembled yours (whether the bearing on the front of the output shaft is in backwards or not

) And of course the new second gear and other various shaft components. Since yours is a early model and they had some crank gear problems on the front.