Raw land valuation from commercial real estate agent reliable?

[Steve Wang]

This is my first post. As a newbie to BiggerPockets, I am amazed at the treasure trove of content and people's willingness to share. I couldn't quite find an answer to this newbie question, however. 

My investors and I are studying a raw land (30+ acres) with mixed-use zoning in a densely populated town. The comps are scarce and a bit dated (2016). The seller has offered a 2-year option, but the purchase price seems a bit steep given the limited data. However, this area is rapidly building up and offers strong economic growth, so it's conceivable that we can exit with worthwhile profit.

A friend has suggested we contact a few local commercial real estate brokers to get some estimates. Since I have never worked with a commercial real estate agency, could someone share if this is a reliable way to get some ballpark figures on raw land?

My apology in advance to any commercial real estate agent for my ignorance. 

Thank you.