Can I update products on multiple opportunity lines at the same time?

Yes, if you have the mass update feature enabled at either the opportunity summary or product tab level, then you can update attributes and apply changes to fields at once on multiple opportunity product lines.

Mass update of attributes at the product line level works similar to the mass update of top-level objects such as opportunities and accounts. The main difference is that your opportunity revenue and product line changes are saved at the product line level. Mass update of changes at the opportunity object level are saved at the parent opportunity level.