Almost, and in some cases yes. But the DUT3C certainly requires more voltage to do so. The DLT3C's default voltage is 1.5v and they can overclock well without going above 1.8v, while a DUT3C's default voltage is 1.65v and will need as much as 1.85v to get up to the speed a DLT3C can hit with 1.775v. Bottom line is the DLT3C's are a little bit better at OC'ing and do it without needing too much juice.
Also, it may be important to check your motherboard's vcore setting. Does it let you set precise voltages? 1.7v, 1.775, 1.8v...etc? Or does it instead use the default voltage and have settings for +.025v, +.05v, +.075v, +.1v? If its the former you have nothing to worry about and should get a DLT#C if you can. If the latter, then you might be limited in hgow much vcore your bios will let you set. For instance if the CPU was 1.5v and your motherboard only aloowed a maximum setting of +.2v, well then you'd have a max voltage of 1.7v. Of course you can bypass this sort of thing by connecting L11 bridges, but a lot of people a a fear of modifying bridges, or just don't want to spend a few dollars on the stuff needed to do it.