Restricted ISO's?

[BulldogTom]

TP is starting a new job with a non-publicly traded company.  He sent me the offer letter because it says check with your tax advisor.   The offer contains a grant of Stock Options.   They also sent a copy of the plan document that governs the Stock Options.   The plan document says the Options can be either ISO or NQSO per the designation of the administrator.   The offer letter does not indicate if they are ISO or NQSO, but the description in the letter matches ISO's to a "t". 

I know the tax rules for an ISO granted to an employee (or NQSO as well), so that is not my question.

The plan also places restrictions on the stock after exercise, that they can only be sold back to the company and cannot be gifted, transferred or used as collateral unless the company goes public in the future.   Is this enough to consider the stock to be restricted?

Thanks

Tom
Modesto, CA