I believe that at every location where you had a rivet there's a depression that you can modify the hood to use the M6.3X1.81 screw and the u-clip. I've a '95 hood here but it's buried bottom side to the wall and I doubt I'll have a chance to get at it early but maybe late in the day.I'll try to post back with a solution OR maybe someone has done it.
The screw you'll need is the same as the liners to the fascia and fender panels on earlier cars with the T-30 Torx or the ones used on the later years with I believe a hex. Here's an Ecklers link to what would have been on the earlier thru likely '92 hoods. Not hinting towards a buy but just showing you what I expect on earlier cars.
http://www.ecklerscorvette.com/corve...1984-1990.html
If you search eBay for 11514290 you can catch a glimpse of the nut that would be used.
http://www.ebay.com/sch/i.html?_from...14290&_sacat=0