Not necessarily, but the slips do have to get use to outdoor living if they happen to be sprouting in the house. Once the slips are hardened up, you can just plant them in the ground , keep the soil damp for a week or so and they will take off. If you have the sweet potato in the house just half submerged in water and place where it can get indirect sunlight for a couple of days, then move into the sun for a couple of days, the pull the slips and plant. Planting the whole sweet potato just results in a crowded mass of competing plants and they need space to grow properly.
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I don't know if this will help you or not, but will post it for your consideration. I have grown them for the past 4 years or so here in S.Jersey. The past couple of years they have developed black discoloration on the skins. I had a couple of Lancaster County gardeners tell me that they cut the slips off the roots and just stick the (rootless) top part of the slip into the ground. It grows fine and the eliminates the black areas on the skin. I'm trying that this year, and so far (after a couple of weeks) the slips without roots are growing just fine. I would encourage you to try it both ways, see which works best for you. I think you'll be okay planting them now.

you can cut that section of tuber out and plant it, see our presentation:

len

Here is a link that might be useful: lens growing sweet spuds and pines

robbiemac, The black discoloration is called scurf. It is a fungal infection. Generally, too wet conditions favor scurf in some varieties. Getting a clean break of the shoot from the potato might help, but doesn't guarantee no scurf.

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Here is the pic. of how I grow Sweet potato slips.Lay the sweet potato on top of the surface of the soil in the pot so that bottom of the tuber stays 1/4 inch in the soil.Keep the pot under partial shade to get morning sun light.In about 10 to 15 days you will see the sprouting slips.As the slips grow in 2 inches or more remove the slips and plant in the pot on side of the tuber.Some slips you pick up from the tuber may have or may not have roots
but once you transplant slips will root in a week's time.Repeat the process as more slips appear on the sweet potato.When slips are 4 to 6 inches high remove from the pot and plant in the garden.If you start the in early May you will have enough slips by first week of June.You may plant the slips now since vines can take little bit of first snow.