30-06 value

As part of the purchase mentioned in an earlier post re. 7mm, we got some 30-06.

This is US surplus (will post headstamp later) that is linked and packed 2 belts in a corroded can. Surprisingly, tha ammo is clean and fresh. My questions are this, the ammo has 4 black tip (a/p) rounds and 1 red tip (tracer???) and is (from memory) late 40's early 50's production with a red sealant ring around the primers. Is this , as I believe, corrosive primed? My rule of thumb is that the red sealant indicates corrosive primers; am I correct for US ammo?

What would be a fair price range for this type of ammo? Is linked ammo "more desirable" (as in higher priced than loose rounds?) for re-sale.