Please test your silicone sealer in modern fuel; If you live in the USA, you are running with a lit fuse.
The rivets are there to prevent the nipples from backing out upon loosening of the nuts for service. It should be obvious to all that after years in service, the fine threads of the nuts and nipples can get frosty
. (Anti-seize compounds were not prescribed in the service manuals, but they are our best hedge against time!)
The most common cause of leakage is stress from over-tightening of the nuts in an attempt to make the unforgiving brass ferrules seal, even when properly annealed. Brass was the best our forefathers had. We enjoy spaceage alternatives today, allowing the assembly to seal with much less force.
Back to rivet replacement:
Seal-Lock "Fluid-Weld" http://silver-seal.com/
is specifically made for peened metal-to-metal adhesion, forming a chemical bond between dissimilar metals.
I first learned of it when "pinning" cracks in castiron engine blocks. (This is a process where a crack is repaired by drilling and tapping into the crack so that a tapered threaded plug can be forced in and peened. Then another hole is drilled and tapped into the crack, overlapping the previous plug. The process is repeated over and over until the entire crack has been stitched up.)
And as it is a permanent bond, it resists heat and solvents.
T'aint cheap, though!