Previous research making claims about students' proving capabilities usually only explored one modality (e.g. oral or written arguments). This study compares the written and oral representations of eighth-grade students' mathematical arguments to determine whether the two modalities portray similar understandings. We replicate Stylianides' (2019) analysis using a different temporal sequencing of oral and written arguments and a larger sample size. Using an existing proof scoring scheme, we found a statistically significant difference between students' written and oral representations of proof. Students often struggled to write arguments they could otherwise represent orally, and we found no evidence that students' written arguments were more sophisticated than their oral arguments. We also share two illustrative cases representing the disparity between students' written and oral arguments. The findings of this study suggest that students' proving capabilities might not be as dire as previous research implies.