I can't remember my scores, but I was diagnosed with GD and had to control it with diet. If anything it was actually a blessing as it stopped me from gaining too much weight, so less to lose after DD was born!

As the 1 hr test is non fasting, it could be a case of what you ate earlier bumping it higher, so the fasting test can be more accurate. As an example, when my sister was pregnant and going for her test, they told her to eat her normal breakfast that day. For her, normal at the time was weetbix with honey and two glasses of orange juice, so naturally her test was off the charts, but after her next test she was given the all clear.