can these be mortared into standard 2x4 or 2x6 construction? The installation guide shows a brick building

Yes. The basics of installing a Clearly Secure window in a wood frame opening are: first remove the existing window sash and hardware. Install an outside ½-in. or ¾-in. parting stop around the exterior window rough opening. Tap rustproof roofing-type nails intermittently around the jambs, head and sill of the wooden window frame, leaving the nail heads set up slightly. Position the Clearly Secure window into the opening and secure in place with shims. Fully pack mortar around the perimeter to fill the space between the glass block and the wood frame rough opening. The mortar will not stick to wood but it will wrap around the nail heads and secure the window in place. When the mortar starts to set, remove any shims and fill in holes. Smooth the mortar joints. (Minimally expanding spray-in insulation can also be used instead of mortar; when using low expansion spray-in insulation leave shims in place and cut shims flush with glass block.) Trim out the window from the interior to create an inside stop. Remember to use a paintable caulk formulated for wood and glass on all joints on the exterior and interior. Make sure to apply caulk sealant between both the stop and glass block window and the stop and the wood frame rough opening on the exterior and interior.