Devil is in the details? Double-trigger RSU for private company

I have an offer with a private company that is offering Double-trigger RSUs as compensation. (First trigger is vesting date, second is liquidity event). After some prodding they admitted the evaluation of the RSUs is based on the latest funding (Series D) round's preferred price. My understanding is this is unorthodox and typically this is done via the 409A value. My concern is here, I'm getting the shares at the preferred price but still receiving common stock. Are they overvaluing their shares and thereby under-compensating me? Thanks in advance for the help.