You guys usually have insight into everything. So, I thought I'd come here looking for an answer. Both BCGs are from the same model ar. The bottom one is significantly lighter than the other. The top has never been fired out of the factory and the lower has a 100 rounds through it? What's up with te difference in color? Just different runs in manufacturing?any possible issues in the future (ie rust or corrosion)? Already sent a pic to the manufacturer but wanted to hear all your opinions first.