if thats the only time you can make it to the gym then that works for ya, better than not going at all.
for me, I always go in the morning before heading out for work, I'll get to the gym around 5:30am... i like this time best b/c it gives me plenty of time to complete my workouts and there's not many people in the gym at time time
the down side of it is, not getting enough rest due to going to sleep late and later in the week i tend to miss my friday workouts.