Using left over pergo boards instead of 2x4 to mount a peg board
Will it work? Yeah probably. Will it work well? Probably not.

When mounting pegboard, the furring strips, 2x4s, or in this case pergo really doesn't take any significant tensile load. What holds the pegboard up is the compression from the fastener pre-loading. 2x4s aren't even necessary, many pegboard kits come with a bunch of plastic spacers. All the pergo has to do is maintain the space between the wall and the pegboard, getting that compressive strength is not very demanding.

So, using your pergo, it's pretty wide, so you are sacrificing a lot of pegboard holes wherever those pergo boards are. If you really want to avoid spending any extra cash, rip the pergo down to 1.5" or 1" wide, it just needs to seperate the pegboard from the wall.

If your wall surface is flat, you don't even need any 2x4s or pergo boards, just use spacers, either plastic spacers from a kit, or just epoxy some hardware store nuts that are large enough for the concrete screws to pass through on the backside, for easy mounting. If the surface is bumpy like a stone wall, then build a frame out furring strips or 2x4s, depending on the level of unevenness.