Tim Engle’s response when asked the question....
I wouldn't be adverse to re-using the bolts that have been re-torqued twice... "IF" I was confident that they were properly torqued previously. Re-using the rod bolts is all about having confidence that they weren't previously abused. If Lotus was the last one in there, I have no problem re-using the rod bolts. If the engine had previously been rebuilt, did that mechanic know what he was doing? If he screwed-up something else, I might have concerns about what he did to the rod bolts, main bearing studs, and head studs... ie, the critical fasteners. Keep balance in mind. That end of the connecting rod is going through some wild gyrations at 7000 rpm, and any change of mass (different bolts) can have significant balance consequences. The stock rods were reasonably well balanced. If you were building a race engine, you might want to be a little more fussy; but as a stock street engine, the 910 was well built. But when you make changes, like replacing one rod out of a set, or replacing rod bolts, it would be good to have a shop check the balance. Talk to your shop. The bottom of the rod caps have twin, parallel ribs running around them. There is no separate sacrificial pad or boss from which material is ground off to lighten it during balancing, so some shops simply grind the bottom of the ribs. NO!! The ribs are structural, and you don't just cut away at them.
I actually have two sets of rod bolts. One set from the engine with the failed thrust washer and one set from the replacement engine. The replacement engine bolts have been torqued twice. The original bolts have only been torqued once by Lotus but have been used in an engine that had excessive crank float.