I think most will agree that breaking in a new pair of boots at OCS is not the best idea. You might consider showing up with a pair you know won't cut your feet up.
Bad feet is bad news
Most people actually show up to OCS without having been in boots before and have no problems. I didn't have any and I didn't buy boots before hand. The cycle actually has boot break in time built into it. Don't buy boots before hand, you don't need to. In fact, the less you bring to OCS the better. But hey, I just went through the most recent class so what do I know.