Brad. I guess they'll be thorough and do the full battery of tests. They might put you in for an OGT (oral glucose tolerance) test and if they suspect you are diabetic in the making, ask them to do a c-peptide assay - that usually sorts out the type 1, type 2 category. I'm type 1 myself and dart myself 4x a day on insulin.
Now, does it interfere with cycling? Hypoglyceamia is always a potential worry, but being prepared for it is the answer. Exercise boosts insulin sensitivity so the more you do the better it is for you. Any exercise (providing there is no injury involved) is usually always beneficial, though sadly, not always enjoyable. Like has been mentioned, most folk are diagnosed as a result of being overweight and often in response to diabetic complications but whether you are or not, cycling has a broad spectrum appeal as it involves both aerobic and anaerobic thresholds so it's a win-win situation! Two for the price of one!
If you do turn out to have DM, those of us already with it, will reluctantly welcome you to our little 'secret' world. Fortunately diabetes is one of the very few chronic diseases where the patient can manage it quite successfully. The complications of the disease are awful, and exercise is one of the great guns in our arsenal, so enjoy your cycling even more.
Let us know how it pans out.