If you regard, that a Black Lightning does not have prop stands nor a main stand for saving weight, 2 nice aluminium bolts make sense in these holes for aIs this the 3/4 by 20tpi hole referred to in KTB? if so supposedly it was for an anti roll bar for a special sidecar never made . However I think it was for the pegs for the modern 1990+ paddock stands. Truly PEI was a future thinker...
paddok stand, whose weight remains in the paddocks during race.