Kerrbe, Were you parked with the slide(s) out or are you referring to it coming unrolled during travel?
There are no slide topper "locks" per se for slide toppers in the extended position. The manufacturers only use an anti-billow device to prevent the topper from billowing/ballooning around while stowed during travel. These devices require the slide topper to be fully retracted in order to operate. So, if you're referring to the topper(s) coming unrolled while extended, no, there are no locks. If you're referring to billowing around while driving, then yes, yours should have provisions to prevent this. Here are a couple of links to the 2 most common anti-billow setups used by Carefree, of course depending upon which style of topper you have. The Holiday Ramblers used the combination topper and window awning setup quite often, as shown in the 2nd link below: