It is a common practice among both well-established and startup companies to gather feedback from potential/actual customers in order to better plan product or service optimizations and future developments.
Most of the times, these incredibly useful exercises are managed previously and independently from the innovation process, missing significant value from players that should be the clear focus of products/services and improved features.
Therefore, it would make sense to include those target potential and existing customers (if any) into at least the research and ideation phases of open innovation initiatives. The cost of inviting and hosting a few more people in the sessions will be minimum (although some incentives should be offered to incentivize participation and reward user feedback) and the benefits of including them in the process can have a tremendous impact in future success.
In theory, users should be able to make more and better contributions to the innovation process when addressing product/service value proposition, main features, and design, but bringing into the mix users with related technical or business skills should translate into surprising contributions to fully leverage innovation success.