Gauge on 2x2 rib?

How do you measure gauge on a 2x2 rib?
The pattern I’m working on says:
28 sts and 26 rows to 4" over k2,p2 rib (unstretched).

When it’s unstretched I don’t see the purl stitches so do I not count them? Or do I just add them into my final total?

You should knit 28 stitches wide and do 26 rows and that should equal a 4" swatch. You still count the purl stitches even though you can’t see them. A gauge count is based on how many stitches are actually made, not necessarily seen. (Does that make sense???)