Yes for Certification. No for Supplier’s Declaration of Conformity.

There are two ways to use FCC label on products. First one is Certification and second one Supplier’s Declaration of Conformity.

1) As FCC informs, for certification using FCC-recognized accredited testing laboratory is required:

Section 2.948 requires that equipment authorized under the certification procedure be tested at an FCC-recognized accredited testing laboratory with the appropriate scope of accreditation.

2) If you are following the second way (Supplier’s Declaration of Conformity), FCC-recognized accredited testing laboratory is not mandatory. However, you may prefer accredited laboratory. FCC explains this as follows:

For equipment authorized using the Supplier’s Declaration of Conformity (SDoC) procedure, it is not necessary to perform the testing at an FCC-recognized accredited testing laboratory, however, an accredited testing laboratory may be used.  The testing laboratory used is required to maintain a description of the test facility, as required by Section 2.948(b).  The description of the test facility does not need to be submitted to the FCC, unless requested.