Officially no, designs posted in the forum are licensed for Personal Use Only. The pertinent paragraphs from the Forum Guidelines are listed here:
If you decide that you want to gift your designs to the world, you can post them in the Free Laser Designs section of the forum. If you post designs anywhere in the forum, other users can use them in accordance with these details: https://community.glowforge.com/t/about-the-free-laser-designs-category/.
This is an act of great generosity! Thank you, and please express your gratitude to the people who choose to do this.
Some designers will work out a paid license with you though if you want to PM them. Be sure to get it in writing to protect yourself. 