sales projection forecasting

am working on a deal to purchase the manufacturing and distribution rights for the North American market for a large ticket item.
The parent manufacturer currently sells about 70 "widgets" per year of which 10-12 are sold in North America. The manufacturer does not in any way actively promote the "widgets" in the North American market and most sales are due to name/product recognition and word of mouth.
They project that the North American market should be able to sell between 40-200 of these "widgets" per year once the North American manufacturiing and distribution hub is established and the "widget" is actively supported and promoted in the country.
My question is.....is there any possible way of validating these projections? Whether it be by requesting other info from the parent mfg or preferably through some sort of formula or estmating method? This is a key area of my search for investment capital for this indeavor.

thanks