Help with Chainsaw Chain/Bar Sizing

I have a Husqvarna Rancher 450. Recently in Walmart, I found a pile of Oregon brand chainsaw bar and chain packages on clearance for $2. I bought 4 even though my chainsaw wasn't explicitly listed on the compatible saws on the packaging. I figure for $8 I would just buy and figure it out later; it would be real nice to have a stack of disposable chains/bars.

Once i got home I noted that the Husqvarna chain is identical to the Oregon chain I purchased for pitch and gauge, but the chains have different number of drive links (Husqvarna has 80 and the Oregon has 78).

Based on my research, as long as the pitch and gauge are the same, my saw should be able to run it (sprocket/chain interface should be the same). I am not sure how they can have the same pitch, be 20" bars, but be a different number of drive links?

My assumption is that as long as I change bar and chain to the Oregon bar and chain I should be able to run them with no issue. I am guessing is the only difference is the two bars are slightly different lengths accounting for the same pitch and just slightly more/less drive links.

Can anyone confirm this for me?