They were National guards actived into service regiments. They were the exact same level of quality and just as 'real soldiers' as all those conscript regiments, which meant they sucked. They did, however, get their entire uniform kit and weapons. The average age probably was higher though, as many of these men were married and had families.
Though, I have to admit, the 15e Voltigeurs didn't suck so much they forced their commander to surrender, which the Belgian National Guard did. GG Guys. You helped the allied cause by being terrible soldiers.