Well, I figured it out!

I found a website called http://www.flightstats.com.

You can track flights within a few days of the current date (i.e the yesterday or tomorrow), and I found my flight listing.

It lists the equipment used as E75. I checked my original itinerary and it said the same thing. To be sure, I checked on other flights by the same airline to see the equipment, and among the listings I found E70, which would seem to indicate ERJ-170. Thus, I’ve come to the conclusion that the airplane I was on was an ERJ-175. That’s the only logical explanation. I must have just miscounted the number of seats. According to the Republic Airways website, their ERJ-175’s have 22 rows (which is what I counted on the plane), but the first row only has two seats on the right-hand side so that means there are a total of 86 seats in the back. This is about what I saw. Looking at a diagram of their layout, I found my seat, and as I expected, it was at the trailing edge of the wing.

Thus to make a long story short, I figured out that I was on an ERJ-175. I think that’s pretty cool seeing as it’s so new to the fleet (accoriding to another site I found, U.S. Airways/Republic only has twelve of them in service!).