Let's ponder this point some more. Since as project managers we actually lead the communication throughout the project and usually are the point of contact for clients, we are the face of the company for them. How we conduct ourselves and how we handle situations will either build or destroy the trust the client has into the organization. Even if team members do not always conduct themselves as the client hopes they would, the project manager is the one who will create the lasting impression. This will also be a major deciding factor for to client in regards to future business. As you interact with the client, always remember that you have a major influence on whether they will give another contract or not. You may also be the first one to get sales inquiries. When they client asks you about another possible project or outright equipment sales, never simply refer them to the sales phone number or email, but ask a few questions and then connect them to sales in a professional way. For example you could write the email to the sales team, keeping the client in copy, where you brief them on the items or services the client is interested in. Then ask them later if they got the requested information or quotation.
This is not about you getting the sale done, but about you building your relationship with the client. However if your company does have a commission for the sales lead creation - not all companies do - then by all means discuss with the Head of Sales to see if you are entitled to the commission.