That Atlas is closer to the Atlas AS7-K than the Atlas AS7-D-H. There's a reason why I've been headcanoning it as "Kamea has no idea what an Atlas II is and she just found an old General's Ace Custom".
It also doesn't follow standard construction rules at all. It mixes DHS and SHS, and IIRC overflows on crits on tabletop due to FF and ES and XL not actually costing anything crit-wise in HBS battletech.
EDIT; I would suggest starting with the base of an AS7-D, add Endo Steel and DHS, replace the CT Lasers with frontal MPLs and Arm Lasers with ERLLs. 13 DHS, 19 tons standard armor, and Guardian ECM or BAP to fill out the last ton and a half. It's the closest you can get. Attached file is my rendition in SSW.