Though in principle I agree with the previous post, one could argue that Polonius would have been surprised.

So much of his policy towards Ophelia, in instructing her to no longer see Hamlet or give any of herself to him, was based on the fact that he thought his love for her was false and that he was out of her league really.  He goes on and on about how it is just a trap "springes to catch woodcocks" or just a flame of youth that will be extinguished once Hamlet comes to his senses as the heir to the throne.

Even Laertes thinks that Hamlet's affection is false and counsels Ophelia to be careful.

So if you believe that Polonius honestly thought Hamlet was out of her league, he likely would have been pleasantly surprised by the idea of Hamlet actually marrying her with the Queen's consent, particularly since it would have more fully vested him in the royalty.  As his goal seems to be to be the best "yes man" ever, this would be a lovely surprise for him.

In Hamlet Act V, scene i, Gertrude's eulogy is brief:

Sweets to the sweet: farewell!

Scattering flowers

I hoped thou shouldst have been my Hamlet's wife;
I thought thy bride-bed to have deck'd, sweet maid,
And not have strew'd thy grave.

Polonius, if he had been alive, would have agreed with anything the King or Queen said.  He would have liked the word the Queen called Ophelia, a "maid" (a virgin), though he knew she might not have been.  (Branagh's film version shows that she wasn't.)  Polonius was paranoid the entire first act that Hamlet had seduced her.  So was her brother, and he jumps into her grave out of overprotectiveness bordering on incestuous jealousy.

Polonius was a fawning fool.  Gertrude might have said that she hoped Ophelia would have been the gravedigger's bride, and he might have agreed.  Alas, I exaggerate...

Not only would Polonius agreed with the marriage, he would have echoed her speech with a long-winded one of his own.  Two hundred words on flowers, death, and marriage.  All of it nonsense.  Remember what Gertrude told him earlier: "More matter and less art."

Polonius was a windbag and a hypocrite.  He used his daughter as a pawn for his own spiteful fetishes and for the King and Queen's vicarious meddling into Hamlet's state-of-mind.