Work-related musculoskeletal disorders (WMSD) pose significant challenges in various industries due to factors like repetitive movements, forceful exertions, and awkward postures. Implementing proactive and reactive strategies, along-side biomechanical assessment tools, is crucial for mitigating these risks. However, advancements in computer-based technologies have created new opportunities in the ergonomics field. From this background, this study aims to compare the performance of an observational method (Rapid Upper Body Limb Assessment—RULA) against a computer-based method (LEA tool) concerning the risk evaluation of awkward postures. For that, biomechanical risk assessments of a single workstation in a Portuguese automotive part company were conducted. Among main findings, this study highlights methodological disparities between the two methods, such as body parts definition and scoring systems, influencing the final risk scores. Both methods have advantages and disadvantages. Observation-based RULA is simple and quick, but neglects task duration, whereas LEA considers the time spent in different postures but omits factors like wrist position and muscle use. In conclusion, the LEA method proved effective for rapid ergonomic assessment. Despite this, a detailed follow-up ergonomic analysis is recommended due to its inherent limitations, including the fact that it only evaluates awkward postures, not assessing other risk factors.