Exposed metal on leads of SCTWA60N120G2-4

[Stoneruin]

I'm using SCTWA60N120G2-4 for one of my power management PCB. However, I saw there is copper exposed on the component leads. Base on IPC 610-H requirement, exposed basic metal on component leads is defect, but it seems to me the expose metal is manufactory's design. I couldn't find any information in the datasheet or the tn1225 mounting instruction for through hole device package. 
Please help
Appreciate everyone!

[RhSilicon]

Unfortunately I have noticed a quality reduction of 78xx/79xx ST components, the TO-220 case attachment tab is half the thickness of the models I found before on devices:

https://www.st.com/resource/en/datasheet/l78.pdf

https://www.ti.com/lit/ds/symlink/lm340.pdf

Apparently the case of this SCCTWA60N120G2-4 was once much better:

https://octopart.com/sctwa60n120g2-4-stmicroelectronics-112853626

[AScha.3]

copper so expensive these days... :)