I've heard rumours about 3.61 being a forced update, but since you just said "ask"... sounds like it's not going to force it yet.
As for what firmware it'll come with, there have been reports of 3.56 or higher PS3s on sale for months. Older stock may still be lingering, but as ddet pointed out: buyer beware. The longer you wait, the more likely the older stock will be gone and only newer stock will exist. At this point, it's probably a fair guesstimate that 70% of PS3s on the shelves will have 3.56 or above.