1SA Factory-verified

GMC · Regular Production Option

Package, option 01

Years 2000, 2008–09, 2014–16, 2018–27 Models 7 Factory citations 22

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Also described as Trim group, ProTrim group, SierraTrim group, option 01

Also documented for Buick Cadillac Chevrolet Pontiac Saturn

Documented applications

Acadia — first generation, Lambda (2007–2017)

2008–2009 Factory-verified

generic wording in a list GM shared with other nameplates.

GM factory document — 2008 gmc acadia 2wd rpo code list, p.1.
GM factory document — 2009 gmc acadia 2wd rpo code list, p.1.

Safari — Second generation (1995–2005)

2000 Factory-verified

GM factory document — 2000 gmc safari 2wd rpo code list, p.1.

Sierra 1500 — Next-Generation (2027)

2027 Factory-verified

all Regular, Double and Crew Cab models; all 1SA models are late availability

GM factory document — 2027 gmc next generation sierra 1500 retail and fleet fleet order guide, p.1.

Sierra HD — K2XX (2015–2019)

2015, 2018–2019 Factory-verified

2018: GM's 2018 Sierra 2500HD order guide; 2019: GM's 2019 Sierra 3500HD order guide

GM factory document — 2015 gmc sierra 2500hd fleet order guide wayback, p.1.
GM factory document — 2018 gmc sierra 2500hd order guide copy gm authority, p.55.
GM factory document — 2019 gmc sierra 3500hd order guide copy gm authority, p.52.

Sierra HD — T1XX (2020–2027)

2020–2022, 2024–2027 Factory-verified

all three vehicles; named base Sierra in 2020 and 2021 and Pro from the 2022 model year (GM Authority 2020, 2021 and 2022 Sierra HD pages; the 2021 page names Sierra 1SA); 2024: GM Authority 2024 changes page names Pro 1SA

GM factory document — 2025 gmc sierra 2500 hd retail and fleet fleet order guide, p.1.
GM factory document — 2026 gmc sierra 2500 hd retail and fleet fleet order guide, p.1.
GM factory document — 2027 gmc sierra 2500 hd retail and fleet fleet order guide, p.1.

Sierra — K2XX (2014–2019)

2014, 2016, 2018–2019 Factory-verified

the base Sierra equipment group (NICB: Fleet/Base).

GM factory document — 2014 gmc sierra 1500 fleet order guide wayback, p.1.
GM factory document — 2016 gmc sierra 1500 fleet order guide wayback, p.1.
GM factory document — 2018 gmc sierra 1500 order guide copy gm authority, p.3.
GM factory document — 2019 gmc sierra 1500 limited double cab k2xx order guide copy gm authority, p.4.

Sierra — T1XX (2019–2026)

2019–2020, 2022–2026 Factory-verified

the 2025 and 2026 guides head this column Pro; NICB prints the base series as Fleet/Base through 2025 and PRO in 2026

GM factory document — 2019 gmc 19 sierra 1500 body builder feb 20, p.9.
GM factory document — 2020 gmc 20 sierra 1500 electrical body buil 1, p.9.
GM factory document — 2022 gmc 22 sierra 1500 new electrical body builder sm en us 2022jul20, p.10.
GM factory document — 2023 gmc 23 sierra 1500 electrical body builder sm en us 2022oct12, p.9.
GM factory document — 2024 gmc 24 sierra 1500 sm electrical body builder esid 23dec12, p.10.
GM factory document — 2025 gmc my25 sierra 1500 electrical bbm, p.8.
GM factory document — 2025 gmc sierra 1500 retail and fleet fleet order guide, p.167.
GM factory document — 2026 gmc sierra 1500 retail and fleet fleet order guide, p.83, p.84.

This page aggregates every documented appearance of 1SA in the GMC reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.