Yes, those are standard Nacra F18 boards. Hobie Tiger boards are very similar. They are a little fatter and shorter than the Nacra 20 and Nacra 17 boards.

A while back, Rick Bliss had a couple of front beams for a Nacra 6.0 - I believe they are the same. One was rigged with hardware and the other without. You should give him a call. A used beam would likely be fine but you may want to make sure that it doesn't have extensive corrosion.

The cast aluminum piece is in a slight "V" shape to match the dolphin striker. It is slightly wider than the dolphin striker material and has a ridge in front and in back of it to keep it centered on the dolphin striker. It is slightly hollowed out on top to fit the mast post. The pressure from the mast post and the fore and aft ridges keep it in place on the dolphin striker. No adhesive is required. Two photos attached.