Is a 401K Roth Deferral the same as a Roth IRA?

In what sense?

1)  At the point the contribution is made....NO. 

ROTH 401k contributions are made thru employer payroll deductions, and are only entered in the software when you put in your W-2 forms. They also have much higher contribution limits than ROTH IRAs.  A ROTH IRA is a separate account you have to set up yourself....almost always outside of your employer.

OR

2)  At the point where you take  distributions?   

<<Edited>>  OK , as noted below somewhat "similar" treatment at distribution.  Depends on the exact situation.

No, they are controlled by different sections of the tax law.  When Turbotax asks if you contributed to a Roth IRA and you had a designated Roth 401(k), the answer to the IRA question is No.

Also, the distribution rules are NOT identical, although they are very similar.