Yes both SemanticForms and SemanticFormInputs are updated via git clone.
However command "grep -r SFIDatePicker ." under both SemanticForms and SemanticFormInputs directories return only calls to the class in SFI_DateTimePicker.php, no class definition.
[root@server1 extensions]# git clone https://git.wikimedia.org/git/mediawiki/extensions/SemanticForms.git
[root@server1 extensions]# git clone https://gerrit.wikimedia.org/r/p/mediawiki/extensions/SemanticFormsInputs.git
[root@server1 extensions]# grep -r SFIDatePicker .
./SemanticFormsInputs/includes/SFI_DateTimePicker.php: $this->mDatePicker = new SFIDatePicker( $this->mInputNumber . '_dp', $dateString, $this->mInputName, $this->mIsDisabled, $this->mOtherArgs );
./SemanticFormsInputs/includes/SFI_DateTimePicker.php: SFIDatePicker::getParameters(),
[root@server1 extensions]#