To be precise, because I'm crazy and obsessive like that, the line in its entirety-
"Tell the truth lad. Do you really think the captain and the squire are plannin' to share the treasure with the likes of us? ...No? And we bein' the rightful owners. Flint's own crew, who SHED OUR BLOOD getting it here! Join us, lad. Donate your compass to the treasure hunt, and get a full share!"
And yes, it comes in the middle of "Professional Pirate." Me likes that song, ja... Heck, me likes the whole movie! But I ramble. Swearing is definately not unheard of with the Muppets. It's certainly not common, but it's not unheard of.