Yep. The former uses some Fidelity managed funds in its allocation; the latter uses only index funds. If you are a Fidelity investor looking for a single asset allocation index fund, a 0.16% ER is worth considering. You can probably do a little better elsewhere, but you are talking about only a few basis points.
If it's a 401k with limited choices, then FFFFX is okay. If it is a Fidelity administered 401k, some offer expanded choices through Fidelity BrokerageLink. This gives you additional options and you could probably build your own three fund portfolio at a lower ER.
There are better Target Date funds. From the link in my previous post, click on the 5-year column to sort the funds by their average annual 5-year after expense returns. T Rowe Price (TRRDX), Schwab (SWERX), and Vanguard (VFORX) have Target Date 2040 funds with better after expense returns than any of the Fidelity options.
Outside a 401k, you could also build your own three fund portfolio at a lower ER.