Howdy @nbuckley !
There are a couple ways to adjust the fit of the bike depending on what you're looking to accomplish. The stem riser you refer to is likely the Delta Cycle Alloy Stem Raiser . There are some sizing considerations to explore/confirm and the potential that you'll need to lengthen the cables/housing. We've used it successfully with many customer bicycles to achieve a more upright riding position. For consideration, you could also explore putting on a shorter stem or a step with a higher angle. In my experience this riser is a little more upright that a stem swap. Thanks for reaching out with your bike questions! Happy Trails!