Paul Reed Smith (PRS) guitars have a reputation as top-end, boutique-quality guitars. Unfortunately, with this level of quality comes a hefty price tag. That's why PRS introduced the cheaper Student Edition (SE) line of guitars. To maintain quality while lowering price, PRS manufactured these guitars in Korea and used some less-costly materials. Although it's sometimes hard to tell exactly what gauge of strings one of these guitars comes with, an educated guess can be made.
A PRS SE guitar straight from the factory will be equipped with PRS guitar strings. PRS only offers six different six-string gauge combinations: .009s (009, .011, .016, .024, .032, .042); .0095s (.0095, .0115, .016, .024, .034, .044); .010s (.010, .013, .017, .026, .036, .046); .011 DGTs with an unwound G string (.011, .014, .018, .028, .038, .049); .011s (.011, .014, .020, .028, .038, .049.); and .012s (.012, .015, .022, .032, .042, .052). Usually guitars come from the factory with one of the thinner gauges of these strings like the .009s, .0095s or .010s.
If a guitar has sat in a guitar store for a long time the employees may have changed the strings. If you think this may be the case, ask a store employee where you bought the guitar from what gauge strings they use to restring instruments. They might also be able to tell you exactly what gauge strings the guitar had when it came from the factory.
If you are not sure what gauge guitar strings your PRS SE came with you can try to place them by playing several different guitars with known string gauges. Experienced guitarists can often feel differences in string gauges. This may help you determine what size strings came on your PRS SE guitar.
You can measure the gauge of guitar strings with scientific calipers. Gauge is actually a measure of the string's diameter, so you would use calipers in the same way you would use them to make extremely small measurements. The calipers should be able to read thousandths of an inch to get any useful data. The more precise your calipers, the better chance you will get an accurate reading.