The Silverhawk is not a trigger plate action, its springs are housed in the action body up front, it has no springs in the back pushing the hammers. The springs are fairly short and stout.

The Excelsior 88 was made by Fausti, if my memory is accurated, it should be easy to get a spring guide from them. It should be a part common to all their products using the same action. Perhaps the original spring was encased in a an external guide cylinder? That would explain why a rod seems to bend in the stock bolt post.

As for having a spring steel bent rod etc, it will cause binding on the spring and unreliable functioning.